An Analysis of Off-grid, Off-pipe Housing in Six U.S. Climates

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This dissertation addresses the issues of climate change and depletion of non-renewable resources of energy and water, and aims at eliminating the use of non-renewable resources of energy and water for the building operation in single-family detached residences in the U.S. With this aim, this study investigated the feasibility of the off-grid, off-pipe design approach in six climate locations across the U.S. to achieve self-sufficiency in a house for building energy, indoor water use, and household wastewater and sewage disposal using only on-site available renewable resources.
For the analysis, a 2,500 ft2, 2000/2001 International Energy Conservation Code standard reference house with typical building and usage characteristics was selected as the base case. The six U.S. climate locations included: Minneapolis, MN, Boulder, CO, Atlanta, GA, Houston, TX, Phoenix, AZ, and Los Angeles, CA. The renewable resources considered for this study included: solar radiation, wind, biomass for building energy needs; rainwater for indoor water use. In addition, the building site was considered for the disposal of household wastewater and sewage. The selected climate locations provided different scenarios in terms of base-case building energy needs and availability of renewable resources. Depending on these, energy and water efficiency measures were selected for reducing the building needs. For the reduced building needs, the sizing of systems for self-sufficiency was performed, including: solar thermal system for building’s space heating and water heating needs, photovoltaic and wind power systems for building’s electricity needs; rainwater harvesting system for indoor water needs; and septic system for the on-site disposal of household wastewater and sewage. In this manner, an integrated analysis procedure was developed for the analysis and design of off-grid, off-pipe homes, and was demonstrated for six U.S. climate locations.
The results of the analysis indicated that achieving self-sufficiency for energy, water and sewage disposal was possible is all climates provided the systems for the collection and storage of renewable resources were large. On the other hand, the utilization of these systems was small for locations, where the year-to-year and seasonal variations in the weather conditions and availability of climate resources was large. For increased system utilization, minimization of the peak building needs, utilization of harvested energy for secondary purposes, and considering alternative systems for such applications are preferred.